My girlfriend bought one last weekend on a whim. It's a nice little unit, and nice to hold. I've got a Sony PRS-350, which requires you to use the Sony software or Calibre to load books on (a fact that has never bothered me), so being able to just drop epub files onto the USB drive the Kobo exports was a surprisingly nice touch.
I'm not actually sure what the wireless bit is used for - maybe it facilitates automatic download of purchased e-books if you buy them through the Web site or Kobo app - but I assume it works because my girlfriend has been happily reading and buying books.